Two battalions of Continental Marines were formed on 10 November 1775 in Philadelphia as a service branch of infantry troops capable of fighting for independence both at sea and on shore.[10] The role of the Corps has since grown and evolved, expanding to aerial warfare and earning popular titles such as, "America's third air force", and, "second land army".[11] The United States Marine Corps has distinguished itself as it has served in the majority of American wars and armed conflicts, from its inception to the modern era, and attained prominence in the 20th century when its theories and practices of amphibious warfare proved prescient and ultimately formed the cornerstone of the Pacific theater of World War II.[12]

This last clause, while seemingly redundant given the President's position as Commander-in-chief, is a codification of the expeditionary responsibilities of the Marine Corps. It derives from similar language in the Congressional acts "For the Better Organization of the Marine Corps" of 1834, and "Establishing and Organizing a Marine Corps" of 1798. In 1951, the House of Representatives'Armed Services Committee called the clause "one of the most important statutory – and traditional – functions of the Marine Corps." It noted that the Corps has more often than not performed actions of a non-naval nature, including its famous actions in Tripoli, the War of 1812, Chapultepec, and numerous counter-insurgency and occupational duties (such as those in Central America), World War I, and the Korean War. While these actions are not accurately described as support of naval campaigns nor as amphibious warfare, their common thread is that they are of an expeditionary nature, using the mobility of the Navy to provide timely intervention in foreign affairs on behalf of American interests.[20]

A U.S. Marine Security Guard reviews a security system at a U.S. embassy in December 2004.

In addition to its primary duties, the Marine Corps conducts Visit, Board, Search, and Seizure (VBSS) operations, as well as missions in direct support of the White House and the State Department. The Marine Band, dubbed the "President's Own" by Thomas Jefferson, provides music for state functions at the White House.[21] Marines from Ceremonial Companies A & B, quartered in Marine Barracks, Washington, D.C., guard presidential retreats, including Camp David, and the Marines of the Executive Flight Detachment of HMX-1 provide helicopter transport to the President and Vice President, with the radio call signs "Marine One" and "Marine Two", respectively.[22] The Executive Flight Detachment also provides helicopter transport to Cabinet members and other VIPs. By authority of the 1946 Foreign Service Act, the Marine Security Guards of the Marine Embassy Security Command provide security for American embassies, legations, and consulates at more than 140 posts worldwide.[23] The relationship between the Department of State and the U.S. Marine Corps is nearly as old as the corps itself. For over 200 years, Marines have served at the request of various Secretaries of State. After World War II, an alert, disciplined force was needed to protect American embassies, consulates, and legations throughout the world. In 1947, a proposal was made that the Department of War furnish Marine Corps personnel for Foreign Service guard duty under the provisions of the Foreign Service Act of 1946. A formal Memorandum of Agreement was signed between the Department of State and the Secretary of the Navy on December 15, 1948, and 83 Marines were deployed to overseas missions. During the first year of the MSG program, 36 detachments were deployed worldwide.[24]

The Marine Corps was founded to serve as an infantry unit aboard naval vessels and was responsible for the security of the ship and its crew by conducting offensive and defensive combat during boarding actions and defending the ship's officers from mutiny; to the latter end, their quarters on ship were often strategically positioned between the officers' quarters and the rest of the vessel. Continental Marines manned raiding parties, both at sea and ashore. America's first amphibious assault landing occurred early in the Revolutionary War on 3 March 1776 as the Marines gained control of Fort Montague and Fort Nassau, a British ammunition depot and naval port in New Providence, the Bahamas. The role of the Marine Corps has expanded significantly since then; as the importance of its original naval mission declined with changing naval warfare doctrine and the professionalization of the naval service, the Corps adapted by focusing on formerly secondary missions ashore. The Advanced Base Doctrine of the early 20th century codified their combat duties ashore, outlining the use of Marines in the seizure of bases and other duties on land to support naval campaigns.

Throughout the late 19th and 20th centuries, Marine detachments served aboard Navy cruisers, battleships and aircraft carriers. Marine detachments (generally one platoon per cruiser, a company for battleships or carriers) served in their traditional duties as a ship's landing force, manning the ship's weapons and providing shipboard security. Marine detachments were augmented by members of the ship's company for landing parties, such as in the First Sumatran Expedition of 1832, and continuing in the Caribbean and Mexican campaigns of the early 20th centuries. Marines would develop tactics and techniques of amphibious assault on defended coastlines in time for use in World War II.[25] During World War II, Marines continued to serve on capital ships. They often were assigned to man anti-aircraft batteries. When gun cruisers were retired by the 1960s, the remaining Marine detachments were only seen on battleships and carriers. Its original mission of providing shipboard security finally ended in the 1990s as the battleships were retired and nuclear weapons were withdrawn from deployment on aircraft carriers.

While the Marine Corps does not employ any unique combat arms, as a force it can rapidly deploy a combined-arms task force to almost anywhere in the world within days. The basic structure for all deployed units is a Marine Air-Ground Task Force (MAGTF) that integrates a ground combat element, an aviation combat element and a logistics combat element under a common command element. While the creation of joint commands under the Goldwater–Nichols Act has improved inter-service coordination between each branch, the Corps' ability to permanently maintain integrated multi-element task forces under a single command provides a smoother implementation of combined-arms warfare principles.[12]

The close integration of disparate Marine units stems from an organizational culture centered on the infantry. Every other Marine capability exists to support the infantry. Unlike some Western militaries, the Corps remained conservative against theories proclaiming the ability of new weapons to win wars independently. For example, Marine aviation has always been focused on close air support and has remained largely uninfluenced by air power theories proclaiming that strategic bombing can single-handedly win wars.[25]

This focus on the infantry is matched with the doctrine of "Every Marine [is] a rifleman", a focus of Commandant Alfred M. Gray, Jr., emphasizing the infantry combat abilities of every Marine. All Marines, regardless of military specialization, receive training as a rifleman; and all officers receive additional training as infantry platoon commanders.[26] For example, at Wake Island, when all of the Marine aircraft were shot down, pilots continued the fight as ground officers, leading supply clerks and cooks in a final defensive effort.[27] As a result, a large degree of initiative and autonomy is expected of junior Marines, particularly the NCOs (corporals and sergeants), as compared with many other military organizations. The Marine Corps emphasizes authority and responsibility downward to a greater degree than the other military services. Flexibility of execution is implemented via an emphasis on "commander's intent" as a guiding principle for carrying out orders; specifying the end state but leaving open the method of execution.[28]

The amphibious assault techniques developed for World War II evolved, with the addition of air assault and maneuver warfare doctrine, into the current "Operational Maneuver from the Sea" doctrine of power projection from the seas.[7] The Marines are credited with the development of helicopter insertion doctrine and were the earliest in the American military to widely adopt maneuver-warfare principles which emphasize low-level initiative and flexible execution. In light of recent warfare that has strayed from the Corps' traditional missions,[29] it has renewed an emphasis on amphibious capabilities.[30]

The Marine Corps relies on the Navy for sealift to provide its rapid deployment capabilities. In addition to basing a third of the Fleet Marine Force in Japan, Marine Expeditionary Units (MEU) are typically stationed at sea. This allows the ability to function as first responders to international incidents. The United States Army maintains light infantry units capable of rapid worldwide deployment, but those units do not match the combined-arms integration of an MAGTF and lack the logistics that the Navy provides.[12] Therefore, the Marine Corps is often assigned to non-combat missions such as the evacuation of Americans from unstable countries and providing humanitarian relief during natural disasters. In larger conflicts, Marines act as a stopgap, to get into and hold an area until larger units can be mobilized. The Corps performed this role in World War I and the Korean War, where Marines were the first significant combat units deployed from the United States and held the line until the country could mobilize for war.[31] To aid rapid deployment, the Maritime Pre-Positioning System was developed: fleets of container ships are positioned throughout the world with enough equipment and supplies for a Marine Expeditionary Force to deploy for 30 days.

The USMC is planning to reduce its logistical requirements and by 2025 eliminate all liquid fuel use for Marine Expeditionary Forces, except for highly efficient vehicles.[32]

Two small manuals published during the 1930s would establish USMC doctrine in two areas. The Small Wars Manual laid the framework for Marine counter-insurgency operations from Vietnam to Iraq and Afghanistan while the Tentative Landing Operations Manual established the doctrine for the amphibious operations of World War II. "Operational Maneuver from the Sea" is the current doctrine of power projection.[7]

The United States Marine Corps traces its institutional roots to the Continental Marines of the American Revolutionary War, formed by Captain Samuel Nicholas by a resolution of the Second Continental Congress on 10 November 1775, to raise two battalions of Marines. That date is regarded and celebrated as the date of the Marine Corps' birthday. At the end of the American Revolution, both the Continental Navy and Continental Marines were disbanded in April 1783. The institution itself would not be resurrected until 11 July 1798. At that time, in preparation for the Quasi-War with France, Congress created the United States Marine Corps.[33] Marines had been enlisted by the War Department as early as August 1797[34] for service in the new-build frigates authorized by the Congressional "Act to provide a Naval Armament" of 18 March 1794,[35] which specified the numbers of Marines to be recruited for each frigate.

British and American troops stationed aboard Hornet and Penguin exchanging small arms fire with Tristan da Cuna in the background during the final engagement between British and American forces during the war.

During the War of 1812, Marine naval detachments took part in some of the great frigate duels that characterized the war, which were the first and last engagements of the conflict. Their most significant contribution, however, was holding the center of General Jackson's defensive line at the Battle of New Orleans, the final major battle and most one-sided engagement of the war. With widespread news of the battle and the capture of the HMS Cyane, HMS Levant and HMS Penguin, the final engagements between British and American forces, the Marines had acquired a well-deserved reputation as expert marksmen, especially in defensive and ship-to-ship actions.[37]

After the war, the Marine Corps fell into a malaise that ended with the appointment of Archibald Henderson as its fifth Commandant in 1820. Under his tenure, the Corps took on expeditionary duties in the Caribbean, the Gulf of Mexico, Key West, West Africa, the Falkland Islands, and Sumatra. Commandant Henderson is credited with thwarting President Jackson's attempts to combine and integrate the Marine Corps with the Army.[37] Instead, Congress passed the Act for the Better Organization of the Marine Corps in 1834, stipulating that the Corps was part of the Department of the Navy as a sister service to the Navy.[38] This would be the first of many times that the existence of the Corps was challenged.

Commandant Henderson volunteered the Marines for service in the Seminole Wars of 1835, personally leading nearly half of the entire Corps (two battalions) to war. A decade later, in the Mexican–American War (1846–1848), the Marines made their famed assault on Chapultepec Palace in Mexico City, which would be later celebrated by the phrase "From The Halls of Montezuma" in Marines' hymn. In the 1850s, the Marines would see further service in Panama and Asia, escorting Matthew Perry'sEast India Squadron on its historic trip to the Far East.[39]

With their vast service in foreign engagements, the Marine Corps played a moderate role in the Civil War (1861–1865); their most prominent task was blockade duty. As more and more states seceded from the Union, about a third of the Corps' officers left the Union to join the Confederacy and form the Confederate States Marine Corps, which ultimately played little part in the war. The battalion of recruits formed for the First Battle of Bull Run (First Manassas) performed poorly, retreating with the rest of the Union forces.[31] Blockade duty included sea-based amphibious operations to secure forward bases. In late November 1861, Marines and sailors landed a reconnaissance in force from the USS Flag at Tybee Island, Georgia, to occupy the Lighthouse and Martello Tower on the northern end of the island. It would later be the Army base for bombardment of Fort Pulaski.[40]

The remainder of the 19th century was marked by declining strength and introspection about the mission of the Marine Corps. The Navy's transition from sail to steam put into question the need for Marines on naval ships. Meanwhile, Marines served as a convenient resource for interventions and landings to protect American lives and interests overseas. The Corps was involved in over 28 separate interventions in the 30 years from the end of the American Civil War to the end of 19th century, with 148 U.S. Marines killed in action fighting against the Confederates in the U.S. Civil War.[41] They would be called upon to stem political and labor unrest within the United States.[42] Under Commandant Jacob Zeilin's tenure, Marine customs and traditions took shape: the Corps adopted the Marine Corps emblem on 19 November 1868. It was during this time that "The Marines' Hymn" was first heard. Around 1883, the Marines adopted their current motto "Semper Fidelis" (Always Faithful).[37]

During World War I veteran Marines served a central role in the late American entry into the conflict, on 6 April 1917. The Marine Corps had a deep pool of officers and NCOs with battle experience, and experienced a small expansion. During the war, the Marines, fighting on the Western Front in France, fought their famed battle at Belleau Wood, creating the Marines' reputation in modern history. While its previous expeditionary experiences had not earned it much acclaim in the Western world, the Marines' ferocity and toughness in France earned them the respect of the Germans. Though Marines and American media reported that Germans had nicknamed them Teufel Hunden as meaning "Devil Dogs", for their reputation as shock troops and marksmen at ranges up to 900 meters, there is no evidence of this in German records (as Teufelshunde would be the proper German phrase). Nevertheless, the name stuck.[44]

U.S. Marines in the trenches in France, February 1918.

The Corps entered the war with 511 officers and 13,214 enlisted personnel, and by 11 November 1918 had reached a strength of 2,400 officers and 70,000 enlisted.[45] African-Americans were entirely excluded from the Marine Corps during this conflict.[46]Opha May Johnson was the first woman to enlist in the Marines; she joined the Marine Corps Reserve in 1918 during World War I, officially becoming the first female Marine.[47] From then until the end of World War I, 305 women enlisted in the Corps.[48]

Between the World Wars, the Marine Corps was headed by Commandant John A. Lejeune, and under his leadership, the Corps presciently studied and developed amphibious techniques that would be of great use in World War II. Many officers, including Lieutenant Colonel Earl Hancock "Pete" Ellis, foresaw a war in the Pacific with Japan and undertook preparations for such a conflict. Through 1941, as the prospect of war grew, the Corps pushed urgently for joint amphibious exercises and acquired amphibious equipment that would prove of great use in the upcoming conflict.[49]

The island of Iwo Jima served as the next area of battle, which began on 19 February 1945. The Japanese had learned from their defeats in the Marianas campaign and prepared many fortified positions on the island, including pillboxes and underground tunnels. The Japanese put up fierce resistance, but American forces reached the summit of Mount Suribachi on 23 February. The mission was accomplished at very high losses, with 26,000 American casualties and 22,000 Japanese.[50]

Despite Secretary Forrestal's prediction, the Corps faced an immediate institutional crisis following the war due to the low budget. Army generals pushing for a strengthened and reorganized defense establishment attempted to fold the Marine mission and assets into the Navy and Army. Drawing on hastily assembled Congressional support, and with the assistance of the so-called "Revolt of the Admirals", the Marine Corps rebuffed such efforts to dismantle the Corps, resulting in statutory protection of the Marine Corps in the National Security Act of 1947.[53] Shortly afterward, in 1952 the Douglas–Mansfield Act afforded the Commandant an equal voice with the Joint Chiefs of Staff on matters relating to the Marines and established the structure of three active divisions and air wings that remain today.

The Korean War (1950–1953) saw the hastily formed Provisional Marine Brigade holding the defensive line at the Pusan Perimeter. To execute a flanking maneuver, General Douglas MacArthur called on Marine air and ground forces to make an amphibious landing at Inchon. The successful landing resulted in the collapse of North Korean lines and the pursuit of North Korean forces north near the Yalu River until the entrance of the People's Republic of China into the war. Chinese troops surrounded, surprised and overwhelmed the overextended and outnumbered American forces. X Corps, which included the 1st Marine Division and the Army's 7th Infantry Division, regrouped and inflicted heavy casualties during their fighting withdrawal to the coast, now known as the Battle of Chosin Reservoir.

The fighting calmed after the Battle of the Chosin Reservoir, but late in March 1953 the relative quiet of the war was broken when the Chinese Army launched a massive offensive on three outposts manned by the 5th Marine Regiment. These outposts were codenamed "Reno", "Vegas", and "Carson". The campaign was collectively known as the Nevada Cities Campaign. There was brutal fighting on Reno hill, which was eventually captured by the Chinese. Although Reno was lost, the 5th Marines held both Vegas and Carson through the rest of the campaign. In this one campaign, the Marines suffered approximately 1,000 casualties, while the Chinese suffered at least twice as many. Marines would continue a battle of attrition around the 38th Parallel until the 1953 armistice.[54]

The Korean War saw the Corps expand from 75,000 regulars to a force of 261,000 Marines, mostly reservists. 30,544 Marines were killed or wounded during the war and 42 were awarded the Medal of Honor.[55]

Vietnam was the longest war for Marines; by its end, 13,091[57][58] had been killed in action, 51,392 had been wounded, and 57 Medals of Honor had been awarded.[59][60] Due to policies concerning rotation, more Marines were deployed for service during Vietnam than World War II.[61]

While recovering from Vietnam, the Corps hit a detrimental low point in its service history caused by courts-martial and non-judicial punishments related partially to increased unauthorized absences and desertions during the war. Overhauling of the Corps began in the late 1970s, discharging the most delinquent, and once quality of new recruits improved, the Corps focused on reforming the NCO Corps, a vital functioning part of its forces.[12]

After the Vietnam War, the U.S. Marines resumed their expeditionary role, participating in the failed 1980 Iran hostage rescue attempt Operation Eagle Claw, the invasion of Grenada (Operation Urgent Fury) and the invasion of Panama (Operation Just Cause). On 23 October 1983, the Marine headquarters building in Beirut, Lebanon, was bombed, causing the highest peacetime losses to the Corps in its history (220 Marines and 21 other service members were killed) and leading to the American withdrawal from the country. The year 1990 saw Marines of the Joint Task Force Sharp Edge save thousands of lives by evacuating British, French and American nationals from the violence of the Liberian Civil War.

During the Gulf War (1990–1991), Marine task forces formed the initial core for Operation Desert Shield, while United States and Coalition troops mobilized, and later liberated Kuwait in Operation Desert Storm.[37] Marines participated in combat operations in Somalia (1992–1995) during Operations Restore Hope, Restore Hope II, and United Shield to provide humanitarian relief.[62] In 1997, Marines took part in Operation Silver Wake, the evacuation of American citizens from the US Embassy in Tirana, Albania.

Following the attacks on 11 September 2001, President George W. Bush announced the Global War on Terrorism. The stated objective of the Global War on Terror is "the defeat of Al-Qaeda, other terrorist groups and any nation that supports or harbors terrorists."[63] Since then, the Marine Corps, alongside other military and federal agencies, has engaged in global operations around the world in support of that mission.

In spring 2009, President Barack Obama's goal of reducing spending in the Defense Department was led by Secretary Robert Gates in a series of budget cuts which did not result in significant changes in the Corps' budget and programs, cutting only the VH-71 Kestrel and resetting the VXX program.[64][65][66] However, the National Commission on Fiscal Responsibility and Reform singled the Corps out for the brunt of a series of recommended cuts in late 2010.[67] In light of budget sequestration in 2013, commandant Amos set a goal of a force of 174,000 Marines.[68] He testified that this was the minimum number that would allow for an effective response to even a single contingency operation, but it would reduce the peacetime ratio of time at home bases to time deployed down to a historical low level.[69]

Headquarters Marine Corps consists of the Commandant of the Marine Corps, the Assistant Commandant of the Marine Corps, the Director Marine Corps Staff, the several Deputy Commandants, the Sergeant Major of the Marine Corps, and various special staff officers and Marine Corps agency heads that report directly to either the Commandant or Assistant Commandant. HQMC is supported by the Headquarters and Service Battalion, USMC providing administrative, supply, logistics, training, and services support to the Commandant and his staff.

The basic framework for deployable Marine units is the Marine Air-Ground Task Force (MAGTF), a flexible structure of varying size. A MAGTF integrates a ground combat element (GCE), an aviation combat element (ACE), and a logistics combat element (LCE) under a common command element (CE), capable of operating independently or as part of a larger coalition. The MAGTF structure reflects a strong tradition in the Corps towards self-sufficiency and a commitment to combined arms, both essential assets to an expeditionary force often called upon to act independently in discrete, time-sensitive situations. The history of the Marine Corps as well has led to a wariness of over reliance on its sister services, and towards joint operations in general.[12]

Marine Corps Forces Special Operations Command (MARSOC) includes: the Marine Raider Regiment, the Marine Raider Support Group, and the Marine Special Operations School. Both the Raider Regiment and the Raider Support Group consist of a headquarters company and three operations battalions. The Special Operations School conducts screening, assessment, selection, training and development functions for MARSOC units.

Although the notion of a Marine special forces contribution to the United States Special Operations Command (USSOCOM) was considered as early as the founding of USSOCOM in the 1980s, it was resisted by the Marine Corps. Then-Commandant Paul X. Kelley expressed the popular belief that Marines should support Marines, and that the Corps should not fund a special operations capability that would not support Marine operations.[88] However, much of the resistance from within the Corps dissipated when Marine leaders watched the Corps' 15th and 26th MEU(SOC)s "sit on the sidelines" during the very early stages of Operation Enduring Freedom while other special operations units actively engaged in operations in Afghanistan.[89] After a three-year development period, the Corps agreed in 2006 to supply a 2,500-strong unit, Marine Forces Special Operations Command, which would answer directly to USSOCOM.[90]

As in the rest of the United States military, Marine Corps ranks fall into one of three categories: commissioned officer, warrant officer, and enlisted, in decreasing order of authority (excluding the Air Force, which does not currently appoint warrant officers). To standardize compensation, each rank is assigned a pay grade.[95]

Commissioned officers are distinguished from other officers by their commission, which is the formal written authority, issued in the name of the President of the United States, that confers the rank and authority of a Marine officer. Commissioned officers carry the "special trust and confidence" of the President of the United States.[20] Marine Corps commissioned officers are promoted based on an "up or out" system in accordance with the Defense Officer Personnel Management Act of 1980.

Note: Insignia for second and first lieutenant shown above are incorrectly depicted as U.S. Army / U.S. Air Force insignia; the U.S. Naval Services (U.S. Navy, U.S. Marine Corps, and U.S. Coast Guard), as well as the U.S. Public Health Service and the National Oceanic and Atmospheric Administration, use insignia bars that do not have beveled edges. (See the illustration of the captain’s insignia for comparison and correct depiction of the non-beveled edge bars.)

Enlisted Marines in the pay grades E-1 to E-3 make up the bulk of the Corps' ranks, usually referred to simply as "Marines". Although they do not technically hold leadership ranks, the Corps' ethos stresses leadership among all Marines, and junior Marines are often assigned responsibility normally reserved for superiors. Those in the pay grades of E-4 and E-5 are non-commissioned officers (NCOs). They primarily supervise junior Marines and act as a vital link with the higher command structure, ensuring that orders are carried out correctly. Marines E-6 and higher are Staff Non-Commissioned Officers (SNCOs), charged with supervising NCOs and acting as enlisted advisers to the command.

The E-8 and E-9 levels have two and three ranks per pay grade, respectively, each with different responsibilities. The First Sergeant and Sergeant Major ranks are command-oriented, serving as the senior enlisted Marines in a unit, charged to assist the commanding officer in matters of discipline, administration and the morale and welfare of the unit. Master Sergeants and Master Gunnery Sergeants provide technical leadership as occupational specialists in their specific MOS. The Sergeant Major of the Marine Corps also E-9, is a billet conferred on the senior enlisted Marine of the entire Marine Corps, personally selected by the Commandant. It is possible however for an enlisted Marine to hold a position senior to Sergeant Major of the Marine Corps as has been the case since the 2011 appointment of Sergeant Major Bryan B. Battaglia to the billet of Senior Enlisted Advisor to the Chairman which is deemed the senior enlisted member of the United States military.

The Military Occupational Specialty (MOS) is a system of job classification. Using a four digit code, it designates what field and specific occupation a Marine performs. Segregated between officer and enlisted, the MOS determines the staffing of a unit. Some MOSs change with rank to reflect supervisory positions, others are secondary and represent a temporary assignment outside of a Marine's normal duties or special skill.

In late June 2016, it was reported that the Marine Corps will be removing the word "man" from 19 key job titles. For example, Basic Infantryman will change to Basic Infantry Marine. Rifleman was to remain unchanged.[96]

Enlisted Marines attend recruit training, known as boot camp, at either Marine Corps Recruit Depot San Diego or Marine Corps Recruit Depot Parris Island. Historically, the Mississippi River served as the dividing line which delineated who would be trained where, while more recently, a district system has ensured a more even distribution of male recruits between the two MCRD facilities. Females attend only the Parris Island depot as part of the segregated Fourth Recruit Training Battalion. All recruits must pass a fitness test to start training; those who fail receive individualized attention and training until the minimum standards are reached. Marine recruit training is the longest among the American military services; it is 13 weeks long including processing and out-processing, compared to the Army's 10 weeks, the Navy's 9 weeks,[98] the Air Forces's 8 1/2 weeks, and the Coast Guard's 8 weeks.

Following recruit training, enlisted Marines then attend The School of Infantry at Camp Geiger or Camp Pendleton. Infantry Marines begin their combat training, which varies in length, immediately with the Infantry Training Battalion (ITB). Marines in all other MOSs other than infantry train for 29 days in Marine Combat Training (MCT), learning common infantry skills, before continuing on to their MOS schools which vary in length.[99]

Left to right: Utility Uniform, Dress Uniform, Service Uniform, and Evening Dress Uniform

The Marine Corps has the most stable and most recognizable uniforms in the American military; the Blue Dress dates back to the early 19th century[31] and the service uniform to the early 20th century. Marines' uniforms are distinct in their simplicity; Marines do not wear unit patches or United States flags on any of their uniforms, nor name tags on their service and formal uniforms. Only a handful of skills (parachutist, air crew, explosive ordnance disposal, etc.) warrant distinguishing badges, and rank insignia is not worn on uniform headgear (with the exception of an officer's garrison service cover). While other servicemembers commonly identify with a sub-group as much as or more than their service (Ranger, submariner, aircrew, etc.), Marine uniforms do not reflect such division.

Marines have four main uniforms: Dress, Service, Utility, and Physical Training (PT). These uniforms have a few minor, but very distinct, variations from enlisted personnel to commissioned and non-commissioned officers. The Marine Corps Dress uniform is the most elaborate, worn for formal or ceremonial occasions. There are four different forms of the Dress uniform. The variations of the dress uniforms are known as "Alphas", "Bravos", "Charlies", or "Deltas". The most common being the "Blue Dress Alphas or Bravos", called "Dress Blues" or simply "Blues".It is most often seen in recruiting advertisements and is equivalent to black tie. There is a "Blue-White" Dress for summer, and Evening Dress for formal (white tie) occasions. Versions with a khaki shirt in lieu of the coat (Blue Dress Charlie/Delta) are worn as a daily working uniform by Marine recruiters and NROTC staff.[100]

The Service Uniform was once the prescribed daily work attire in garrison; however, it has been largely superseded in this role by the utility uniform. Consisting of olive green and khaki colors, it is commonly referred to as "Greens". It is roughly equivalent in function and composition to a business suit.[100]

The Utility Uniform, currently the Marine Corps Combat Utility Uniform, is a camouflage uniform intended for wear in the field or for dirty work in garrison, though it has now been standardized for regular duty. It is rendered in a distinctive MARPAT pixelated camouflage (sometimes referred to as digitals or digies) that breaks up the wearer's shape, and serves to distinguish Marine uniforms from those of other services. In garrison, the woodland and desert uniforms are worn depending on the Marine's duty station.[101] Marines consider the utilities a working uniform and do not permit their wear off-base, except in transit to and from their place of duty and in the event of an emergency. This, too, distinguishes them from other services, which have less stringent restrictions.[100]

As in any military organization, the official and unofficial traditions of the Marine Corps serve to reinforce camaraderie and set the service apart from others. The Corps' embrace of its rich culture and history is cited as a reason for its high esprit de corps.[20]

Eagle, Globe and Anchor along with the U.S. flag, the Marine Corps flag and the Commandant's flag.

Two styles of swords are worn by Marines: the officers' Mameluke Sword, similar to the Persian shamshir presented to Lt. Presley O'Bannon after the Battle of Derna, and the Marine NCO sword.[31] The Marine Corps Birthday is celebrated every year on 10 November in a cake-cutting ceremony where the first slice of cake is given to the oldest Marine present, who in turn hands it off to the youngest Marine present. The celebration includes a reading of Commandant Lejeune's Birthday Message.[105] Close Order Drill is heavily emphasized early on in a Marine's initial training, incorporated into most formal events, and is used to teach discipline by instilling habits of precision and automatic response to orders, increase the confidence of junior officers and noncommissioned officers through the exercise of command and give Marines an opportunity to handle individual weapons.[106]

An important part of the Marine Corps culture is the traditional seafaring naval terminology derived from its history with the Navy.

The Corps encourages the idea that "Marine" is an earned title and most Marine Corps personnel take to heart the phrase "Once a Marine, Always a Marine". They reject the term "ex-Marine" in most circumstances. There are no regulations concerning the address of persons who have left active service, so a number of customary terms have come into common use:[53]

"Marine" is acceptable and considered complimentary by most Corps personnel.

"Former Marine" or "Veteran Marine" is acceptable in referring to anyone who has been honorably discharged from the Corps.

"Retired Marine" is generally reserved for those who have completed 20 or more years of service are called "Lifers" and formally retired or those who have been medically retired.

According to one of the "Commandant's White letters" from Commandant Alfred M. Gray, Jr., referring to a Marine by their last earned rank is appropriate.[115]

In 2001, the Marine Corps initiated an internally designed martial arts program, called Marine Corps Martial Arts Program (MCMAP). Due to an expectation that urban and police-type peacekeeping missions would become more common in the 21st century, placing Marines in even closer contact with unarmed civilians, MCMAP was implemented to provide Marines with a larger and more versatile set of less-than-lethal options for controlling hostile, but unarmed individuals. It is a stated aim of the program to instill and maintain the "Warrior Ethos" within Marines.[116] The Marine Corps Martial Arts program is an eclectic mix of different styles of martial arts melded together. MCMAP consists of punches and kicks from Taekwondo and Karate, opponent weight transfer from Jujitsu, ground grappling involving joint locking techniques and chokes from Brazilian jiu-jitsu, and a mix of knife and baton/stick fighting derived from Eskrima, and elbow strikes and kick boxing from Muay Thai. Marines begin MCMAP training in boot camp, where they will earn the first of five available belts.[117]

As of 2013, the typical infantry rifleman carries $14,000 worth of gear (excluding night-vision goggles), compared to $2,500 a decade earlier. The number of pieces of equipment (everything from radios to trucks) in a typical infantry battalion has also increased, from 3,400 pieces of gear in 2001 to 8,500 in 2013.[118]

The Marine Corps utilizes a variety of direct-fire rockets and missiles to provide infantry with an offensive and defensive anti-armor capability. The SMAW and AT4 are unguided rockets that can destroy armor and fixed defenses (e.g., bunkers) at ranges up to 500 meters. The smaller and lighter M72 LAW can destroy targets at ranges up to 200 meters.[122][123] The Predator SRAW, FGM-148 Javelin and BGM-71 TOW are anti-tank guided missiles. The Javelin can utilize top-attack profiles to avoid heavy frontal armor. The Predator is a short-range fire-and-forget weapon; the Javelin and TOW are heavier missiles effective past 2,000 meters that give infantry an offensive capability against armor.[124]

The USMC is currently seeking to purchase commercial off-the-shelf bullet-trap or shoot-through rifle-grenades.[125] These grenades will provide individual Marines additional firepower and will allow indirect fire against targets in defilade, behind walls and buildings or rooftops and elevated positions at ranges between 30 and 150 meters.[125]

In addition, the Corps operates its own organic aerial refueling and electronic warfare (EW) assets in the form of the KC-130 Hercules and EA-6B Prowler, respectively. The Hercules doubles as a ground refueler and tactical-airlift transport aircraft. The Prowler is one of the only two active tactical electronic warfare aircraft left in the United States inventory, and has been labeled a "national asset"; it is used along with the Navy's EA-18G Growlers to assist in any American combat action since the retirement of the Air Force's EW aircraft.[138] The Marine Corps plans to retire the Prowlers by September 2016 and after that time EW capability will come from Marine Air-Ground Task Force Electronic Warfare, which is a strategy where every platform contributes and functions as a sensor, shooter and sharer.[139]

In April 2016 it was reported that the vast majority of USMC aircraft were not capable of flight due to the toll of long wars in Afghanistan and Iraq, the fight against ISIS and budget cuts precluding the purchase of the parts needed to fix an aging fleet. Official statistics confirm that, of 276 F/A-18 Hornet strike fighters in the Marine Corps inventory, only about 30% are ready to fly; and only 42 of 147 heavy-lift CH-53E Super Stallion helicopters are airworthy. Average monthly flight time per pilot has dropped from an average of between 25 and 30 hours in 2006 to just over 4 hours in 2016.[142]

In general, the Marine Corps shares many resources with the other branches of the United States military. However, the Corps has consistently sought to maintain its own identity with regard to mission, funding, and assets, while utilizing support available from the larger branches. While the Marine Corps has far fewer installations both in the U.S. and worldwide than the other branches, many Army posts, Naval stations, and Air Force bases have a Marine presence. They also cross train with other countries.

The Marine Corps' counterpart under the Department of the Navy is the United States Navy. As a result, the Navy and Marine Corps have a close relationship, more so than with other branches of the military. Whitepapers and promotional literature have commonly used the phrase "Navy-Marine Corps Team",[143][144] or refer to "the Naval Service". Both the Chief of Naval Operations (CNO) and Commandant of the Marine Corps report directly to the Secretary of the Navy.

Training alongside each other is viewed as critical, as the Navy provides transport, logistical, and combat support to put Marine units into the fight, such as maritime prepositioning ships and naval gunfire support. Most Marine aviation assets ultimately derive from the Navy, with regard to acquisition, funding, and testing, and Navy aircraft carriers typically deploy with a Marine squadron alongside Navy squadrons. Marines do not recruit or train noncombatants such as chaplains or medical/dental personnel; naval personnel fill these roles. Some of these sailors, particularly Hospital Corpsmen and Religious Programs Specialists, generally wear Marine uniforms emblazoned with Navy insignia. Conversely, the Marine Corps is responsible for conducting land operations to support naval campaigns, including the seizure of naval and air bases. Both services operate a network security team in conjunction.

Marines and Sailors share many naval traditions, especially terminology and customs. Marine Corps Medal of Honor recipients wear the Navy variant of this and other awards;[25] and with few exceptions, the awards and badges of the Navy and Marine Corps are identical. Much of testing for new Marine Corps aircraft is done at NAS Patuxent River. The Navy's Blue Angels flight demonstration team is staffed by both Navy and Marine officers and enlisted men, and includes a Marine C-130 Hercules aircraft.[25]

In 2007, the Marine Corps joined with the Navy and Coast Guard to adopt a new maritime strategy called A Cooperative Strategy for 21st Century Seapower that raises the notion of prevention of war to the same philosophical level as the conduct of war.[145] This new strategy charts a course for the Navy, Coast Guard and Marine Corps to work collectively with each other and international partners to prevent regional crises, man-made or natural, from occurring or reacting quickly should one occur to avoid negative impacts to the United States.

The Marines have reduced the requirement for large amphibious ships from 42 to a bare minimum of 33 ships; the fleet currently stands at 29 ships and is likely to shrink in the future.[146]

The Marine Corps combat capabilities in some ways overlap those of the United States Army, the latter having historically viewed the Corps as encroaching on the Army's capabilities and competing for funding, missions, and renown. The attitude dates back to the founding of the Continental Marines, when General George Washington refused to allow the initial Marine battalions to be drawn from among his Continental Army. Most significantly, in the aftermath of World War II, Army efforts to restructure the American defense establishment included the dissolution of the Corps and the folding of its capabilities into the other services. Leading this movement were such prominent Army officers as General Dwight D. Eisenhower and Army Chief of StaffGeorge C. Marshall.[53] With most of the 2000s spent in operations in Afghanistan and Iraq, Secretary of Defense Robert Gates has voiced concerns that the Marines are becoming a "second Army".[29]

Doctrinally, the Marine Corps' focus is on being expeditionary and independent, and places emphasis on amphibious mobility and combined arms; these make it a much lighter force than many units of the Army. A larger percentage of the Marine Corps' personnel and assets are in the combat arms (infantry, artillery, armor, and close air support) than the Army. However, the Army maintains much larger and diverse combat arms (infantry, armor, artillery, special operations), ground transport, and logistics, while the Marines have a more diverse aviation arm (which constitutes a larger percentage of forces), and is usually organic to the MAGTF. Marines operate as expeditionary units and are completely amphibious. The Marine Corps focus is on standardized infantry units with the other arms in support roles, as the "Every Marine a rifleman" creed shows. This commitment to standardized units can be seen in the short-lived experiment of the Marine Raiders, born in World War II, which was controversial, while the U.S. Army's 75th Ranger Regiment, also born in World War II, enjoys high prestige to this day. The Army has a longer continuous tradition of special operations forces; the Marines joined the Special Operations Command with the establishment of MCSOCOM Detachment One in 2003.[89]

The Marines often leverage the Army's acquisition of ground equipment (as well as benefiting from Army research and development resources), training resources, and other support concepts. The majority of vehicles and weapons are shared with, modified, or inherited from Army programs.

Culturally, Marines and soldiers share most of the common U.S. military slang and terminology, but the Corps utilizes a large number of naval terms and traditions incompatible with the Army lifestyle, as well as their own unique vernacular. Many Marines regard their culture to have a deep warrior tradition, with the ethos that "Every Marine a rifleman" and emphasis on cross-training and combat readiness despite actual job, be it infantry or otherwise. One source states Marines tend to decentralize and push leadership to lower levels, while fostering initiative to a greater degree.[147]

The Air Force traditionally provides the Joint Force Air Component Commander who controls "sorties for air defense, and long range interdiction and reconnaissance" while the MAGTF commander retains control of the Marines' organic aviation assets.[148][149]

The Marine Corps accounts for around six percent of the military budget of the United States. The cost per Marine is $20,000 less than the cost of a serviceman from the other services, and the entire force can be used for both hybrid and major combat operations,[150] enabling it to carry out full-scale military action, peacekeeping operations and humanitarian aid – the entire Three Block War. Note that these per capita costs do not account for support provided by the Navy and other branches, such as the Navy's amphibious warfare ships and long-range air transport by the USAF.[151] However given expected defense budget cuts, the Marines are well positioned for "fielding cheap options for an uncertain world."[152] The Marine Corps budget is comparably well handled with a tiny fraction of the Anti-Deficiency Act violations of any of the other three major branches.[153] In 2013, the USMC became the first American military branch to ever have a fully audited annual budget.[154]

^Garand, George W. & Truman R. Strobridge (1971). "Part II, Chapter 1: The Development of FMFPac". Western Pacific Operations. History of U.S. Marine Corps Operation in World War II, Volume IV. Historical Branch, HQMC, United States Marine Corps. Retrieved 3 August 2008.

^The United States Coast Guard is smaller, about one-fifth the size of the U.S. Marine Corps, but it is part of United States Department of Homeland Security and does not normally operate under the DoD except during times of war and as directed by the U.S. president. The USMC is the largest marine corps force in the world and is larger than the armed forces of many significant powers; for example, the USMC is larger than the active duty Israel Defense Forces.

^Clinton, William J. (2000). "Remarks Celebrating the 200th Anniversary of the United States Marine Corps Band 10 July 1998". In Office of the Federal Register. Public Papers of the Presidents of the United States, William J. Clinton, 1998, Book 2: July 1 to December 31, 1998. Government Printing Office. p. 1217. ISBN978-1-4034-4551-3. The Marine Band played at Thomas Jefferson's Inauguration in 1801 and hasn't missed a single one since. Jefferson was a violin player who loved music almost as much as he loved freedom. He named the band "The President's Own".

^"Report on Marine Corps Duplication of Effort between Army and Navy". U.S. Marine Corps. 17 December 1932.Contains a very detailed account of almost all the actions of the Continental Marines and USMC until 1932. It is available in scanned TIFF format from the archives of the Marine Corps University.

^"Marine Corps History, Customs, and Courtesies". U.S. Marine Guidebook. United states Marine Corps. 2010. p. 37. ISBN978-1-60239-941-9. Marines fought like teufel hunden, legendary wild, devil dogs that at one time roamed the forests of northern Germany

^Myers, Thomas (1988). "Hearts of Darkness". Walking Point: American Narratives of Vietnam. Oxford University Press, USA. p. 114. ISBN978-0-19-505351-7. He reminds his charges that "at Belleau Wood the Marines were so vicious that the German infantrymen called them Teufel-Hunden – 'devil dogs'

^Waseleski, Michael (2009). To Lead by the Unknowing, to Do the Unthinkable. AuthorHouse. p. 5. ISBN978-1-4389-5676-3. the 5th and 6th Marine Regiments earned the nickname of "Teufel Hunden" (devil dog) by the Germans in World War I during the 1918 Château-Thierry campaign near the French village of Bouresches, the Battle of Belleau Wood

^Rottman, Gordon (2011). "GI and Gyrene Jargon US Army and Marine Corps Slang". FUBAR F***ed Up Beyond All Recognition: Soldier Slang of World War II. Osprey Publishing. p. 49. ISBN978-1-84908-653-0. based on Chinese pronunciation of Marine

^"Marine Corps History, Customs, and Courtesies". U.S. Marine Guidebook. United states Marine Corps. 2010. p. 37. ISBN978-1-60239-941-9. In 1804 the Secretary of the Navy ordered Marines to wear black leather stock collars when on duty

^Rottman, Gordon (2011). "GI and Gyrene Jargon US Army and Marine Corps Slang". FUBAR F***ed Up Beyond All Recognition: Soldier Slang of World War II. Osprey Publishing. p. 51. ISBN978-1-84908-653-0. Most likely it was the pillbox cap and high stiff collar making a Marine appear similar to a Mason jar

^Santamaria, Jason A.; Vincent Martino; Eric K. Clemons (2005). The Marine Corps Way: Using Maneuver Warfare to Lead a Winning Organization. McGraw-Hill Professional. p. 149. ISBN978-0-07-145883-2. Long before Hollywood popularized it, Marines used the phrase to reflect their preference for being a fluid, loosely reined force that could spontaneously react to rapidly changing situations, rather than a rigid outfit that moved in a specific direction with a precise plan.

^Freedman, David H. (2000). Corps Business: The 30 Management Principles of the U.S. Marines. New York: Collins.